In the past there has long been a problem with deterioration of effectiveness of underground insulated electrical distribution cables. The cause of this problem has been traced to moisture from various sources which, over time, causes “tree formations” in the cable insulation with the result that the breakdown voltage level falls below the operating level of the network reducing the expectant life of the network by as much as seventy five percent. This problem is described in substantial detail in U.S. Pat. No. 4,545,133, dated Oct. 8, 1985, which was assigned to the American Power Association. Although the cause of the problem was described in that patent, the apparatus and method to overcome it, which were disclosed in that patent, have not been adopted in the field to any significant extent and, the solution proposed in that patent in any event has not resolved the long outstanding problems in the field.
This invention provides an improved method and apparatus for treating the problem of moisture in underground power cables.